An ancient method of turning soft steel into hard steel.

Surface saturation of steel with carbon increases its hardness and wear resistance. This process is called cementation. With its help, at home, you can significantly improve any steel tool made from a low-quality alloy.

What you will need:

bugle;
charcoal;
profile pipe or sheet steel.

The process of carburizing steel at home

The process involves placing a mild steel product into a container filled with charcoal. Then they are heated red-hot and kept at this temperature for a couple of hours. During this time, the surface of the steel is saturated with carbon, which makes it harder.
Depending on the size of the product for cementation, a piece of profile pipe or a box welded from sheet steel can be used as a container for it.

The bottom is welded to the prepared bowl.

Next, you need to grind the charcoal into crumbs and pour it into the bottom of the container, then the product for carburizing is placed in it. The container is completely filled with coal and brewed.

The container with the workpiece is placed in the forge and heated red hot.Based on the color of the tarnish, you need to maintain a temperature of 950-1000°C. To carburize 1 mm of steel, heating must continue for 5 hours. Naturally, the entire thickness of the metal does not need to be made solid; only a thin surface layer is sufficient.

After holding the workpiece for the required amount of time, it is necessary to remove it from the forge and lay it on the sand to cool. After cooling, the container is cut and the product is removed.

A carburized tool will become lighter in color and hard.

It needs to be heated again without the container and cooled sharply in water.

Tempering will rebuild the structure of the metal, making it very hard. After carburizing for 1 hour, even an ordinary nail will be harder than a file and will be able to work as a core on any steel.